In general, side plates of a main frame, serving as a portion of a casing of an air-conditioning apparatus for vehicle, include many parts, such as a bent member and a reinforcement, joined by welding. Each side plate includes two segments for an indoor chamber and an outdoor chamber and the segments are joined to each other after assembly of the chambers. Additionally, the side plate is provided with many parts, for example, an attachment member used to attach the air-conditioning apparatus for vehicle to a railroad vehicle, a hanging fitting used to hang the air-conditioning apparatus for vehicle, a cover attachment fitting used to attach a cover to the main frame, and a reinforcing member for enhancing the strength of the side plate in order to prevent deformation after attachment to the railroad vehicle or upon hanging, the parts being attached to the side plate by welding (refer to Patent Literature 1, for example).